How to Improve OE Sub Bass Quality and Eliminate Vibrations

[Nikko]

Considering how little visibility there is through the ports, you could probably do the job with a Sharpie or other permanent marker rather than worrying about spraying it (either that or just use a small 1" trim roller to coat the area. Either that or do what Bassoony, tadda, and others have done with cloth, screen, etc.

One note if using grill-cloth like Bassoony... although audibly invisible, many are more than dense enough to cause loss of pressure... which can defeat the purpose of the ports entirely. They're fine in front of transducers with limited extension, but not as good for actual ports where volume and pressure are the key parameters.

HA! That's exactly what I did - giant Sharpie! It's not perfect since the finish isn't quite right obviously, but nobody would ever know except me (and now everyone on this forum).

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[Nikko]

I've done the wadding n foam but I've not done the port yet I've not noticed a huge difference yet but I suppose the question is are the ports necessary for it to make a solid improvement as I'm a bit nervous about putting holes in my new car

I was scared to cut mine as well, but it's really a breeze. I bet I measured 5 times before cutting though! It's amazing how much air is forced out of those ports when the music is on. You just think about where all of that was going before you cut the holes ... crazy.

 

[Chappers]

I'll have to get the ports on order

 

[Chappers]

Suppose these would work instead to cover the hole?

 

[Nikko]

Suppose these would work instead to cover the hole?

Yep, I think there is somebody earlier in this thread that uses those or something very similar. Take a look at it and see if you like the look of them compared to the ports.

 

[Loco38SUP]

Has anyone tried using these speaker grills? Seems like it kills two birds with one stone; it allows air to escape, but prevents anything from getting into the holes.

That’s exactly what I did. I cut square pieces from old Pioneer grills I had laying around. Then I just held them in place with Dynamat sound deadener.

Also I installed Polyfil but quickly removed it because the sound was bad with it inside the enclosure.

-RJM

 

[Wj100]

I went ahead and did one part of this mod today... Just filling the subwoofer box with the poly filling. I thought I'd see how it sounded before I did the additional foam padding and the ports. Honestly, I don't know if I feel the need to do the other two parts of the project because the vibration reduction is so significant.

Does porting the box make a big difference in anyone's opinion?

PS, I really can't believe they ship these cars with the subs sounding so awful, but I'm very appreciative of this forum for supplying such an easy fix...

 

[tadda]

I went ahead and did one part of this mod today... Just filling the subwoofer box with the poly filling. I thought I'd see how it sounded before I did the additional foam padding and the ports. Honestly, I don't know if I feel the need to do the other two parts of the project because the vibration reduction is so significant.

Does porting the box make a big difference in anyone's opinion?

PS, I really can't believe they ship these cars with the subs sounding so awful, but I'm very appreciative of this forum for supplying such an easy fix...

I just recently posted this reply about a week ago because someone asked the same question

Adding ports is roughly 85% of the solution to the problem!

Adding ports to the narrow rear panel relieves the back pressure released against the panel that is causing a majority of rattling and vibration...Also adding the exhaust ports is eliminating destructive back pressure which causes low bass distortions and limiting low bass response...

At the very least remove that narrow rear panel if you want better bass response and reduced rattling and vibration...
---------------

Side note:
Do not stuff or fill up the chambers! Stuffing the chamber will drastically diminish bass response and increase rattle....Your better off doing nothing than stuffing them!

Conversely, padding the sidewalls with thin polyfill sheet is done to eliminate any destructive side wall acoustic reflections which "effectively" increases the volume and in turn improve overall bass response....

 

[Wj100]

I just recently posted this reply about a week ago because someone asked the same question

Adding ports is roughly 85% of the solution to the problem!

Adding ports to the narrow rear panel relieves the back pressure released against the panel that is causing a majority of rattling and vibration...Also adding the exhaust ports is eliminating destructive back pressure which causes low bass distortions and limiting low bass response...

At the very least remove that narrow rear panel if you want better bass response and reduced rattling and vibration...
---------------

Side note:
Do not stuff or fill up the chambers! Stuffing the chamber will drastically diminish bass response and increase rattle....Your better off doing nothing than stuffing them!

Conversely, padding the sidewalls with thin polyfill sheet is done to eliminate any destructive side wall acoustic reflections which "effectively" increases the volume and in turn improve overall bass response....

Thanks I just noticed I should have read this thread more carefully before embarking on this project. I watched a couple YouTube videos instead.

So... I did stuff the chamber pretty full... I can probably yank some out, but overall the rattles that were present before the stuffing are indeed gone.

I'll go ahead and do the porting though as well. Thanks again.

 

[tadda]

Thanks I just noticed I should have read this thread more carefully before embarking on this project. I watched a couple YouTube videos instead.

So... I did stuff the chamber pretty full... I can probably yank some out, but overall the rattles that were present before the stuffing are indeed gone.

I'll go ahead and do the porting though as well. Thanks again.

Yeah, careful with following those youtube videos that tried to deviate from my original writeup as they make some careless mistakes and shortcuts!

Not surprised the rattles are gone after overstuffing the enclosures as you most definetly reduced low bass response!

 

[Wj100]

Yeah, careful with following those youtube videos that tried to deviate from my original writeup as they make some careless mistakes and shortcuts!

Live and learn I suppose. So do you recommend I try and pull out some of the poly-fill I crammed in there? Appreciate all of your expertise on this matter.

 

[tadda]

Live and learn I suppose. So do you recommend I try and pull out some of the poly-fill I crammed in there? Appreciate all of your expertise on this matter.

Yes!! As I just mentioned do not stuff or fill up the chambers! Stuffing the chamber will drastically diminish bass response and increase rattle....Your better off doing nothing than stuffing them!

Conversely, padding the sidewalls with thin polyfill sheet is done to eliminate any destructive side wall acoustic reflections which "effectively" increases the volume and in turn improve overall bass response....

 

[Bassoonytoon]

Yeah, careful with Not surprised the rattles are gone after overstuffing the enclosures as you most definetly reduced low bass response!

Polyfill can definitely reduce the vibrations but that includes the actual sound from the speaker. I tried over-filling it when I first did this mod - like others, to try to eliminate vibrations. It definitely got rid of the rattles caused by the bass, but also made lower frequencies (below ~80Hz) very weak.

I tried removing some and kept testing the sound as I went. As you take some out, this has the effect of making the sub box seem bigger (not necessarily a good thing). The only way it finally sounded acceptable was after completely removing the polyfil and just using the foam on the outside of the enclosure.

No polyfil is significantly better than any polyfil.

This car’s audio setup is a conundrum. On one hand, it’s pretty well balanced, has a very useful EQ, the amp responds very well when turning up the power, it has sub boxes that seem to be sized correctly for the speakers, has a separation in the sub box to reduce standing waves/phase issues, and even has ports integrated into the box.

On the other hand, these ports lead to a wall that spreads the air/waves out into the surrounding interior panels and even into the other sub’s port, thus creating those standing waves they tried to avoid in the sub box itself… not to mention that the sub box is metal (probably one of the worst materials for a speaker box) with no thought into reducing ringing/vibrations.

Right now, I’m using the foam on the outside of the box, the ports, and nothing inside the box. As @tadda said, this fixes probably 85-90% of the issues. Doing just these really makes an enormous difference to the sound quality. How it didn’t come like this from the factory is pretty astounding given the level of detail that went into the rest of the system.

 

[tadda]

Somewhere along the way my original instructions regarding the enclosure were changed by some in what I suspect was meant to be a harmless shortcut which actually resulted in a undesirable dimished bass response....Using loose polyfil to stuff the enclosure was never suggested...

That said I found through testing that lining the metal walls with a 1/2" sheet material did make a noticeable difference in improving lower bass response for the very reasons I mention earlier...

Indeed as I also mention in my original post I was pretty taken back myself that the engineers at Toyota/ BMW overlooked some of these obvious design flaws....Thankfully though these are relatively cheap and easy fixes!

 

[Wj100]

Per my previous post, I made the mistake of following YouTube instructions instead of this post and stuffed my sub enclosure with poly-fill. Anyone have any ideas on the best way to remove it without taking apart the enclosure? Not sure how difficult it's going to be to try and pull it out with a screwdriver or something similar....?

Thanks!

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